Printing apparatus with font alignment means

ABSTRACT

A printing apparatus of the type having an image carrier, a color carrier, a font with a plurality of raised, selectively positionable characters, and a piston assembly whereby activation of the piston assembly causes an image to be transferred from the color carrier to the image carrier. The printing apparatus also includes means for varying the force propelling a portion of the piston assembly toward the font, means for insuring proper alignment of said font and means for advancing the image carrier and the color carrier during the printing cycle.

United States Patent 1191 Bluem et al.

14 1 Oct. 14, 1975 [54] PRINTING APPARATUS WITH FONT ALIGNMENT MEANS [75l Inventors: Gary R. Bluem, Minneapolis;

Ronald W. Millman, Bloomington, both of Minn.

[73] Assignee: Kroy Industries Inc., Minneapolis,

' Minn.

[22 Filed: Jan. 30, 1973 21 Appl. No.: 328,066

52] 1 US. Cl. l97/6.7; 101/18; 197/151 51 int. c1. B41J 1/30 58 Field 61 Search 197/6.26.7, 197/16, 18, 49, 53, 151; lO1/18, 19, 398

[56] References Cited I UNITED STATES PATENTS 3,198,168 8/1965 Grupe 197/6.6 X 3,237,747 3/1966 Frechette et 197/151 X 3,272,301 9/1966 Craig 197/6.7 3,308,749 3/1967 Dowd lOl/398 X 3,323,629 6/1967 Stettner 197/6.7 3,391,773 7/1968 Nicole et a1. 197/6.7

3,428,158 2/1969 Brown 197/6.6 3,643,774 2/1972 Kondur l97/6.7 x 3,724,633 4 1973 Korb et al 197/151 3,726,380 4/1973 Beers et al. l97/6.6 3,753,482 8/1973 Brown et al. l97/6.6 3,768,619 10/1973 Lewis 101/18 x Primary Exam'inerEdgar S. Burr Assistant Examiner-R. T. Rader Attorney, Agent, or Firm-Dorsey, Marquart, Windhorst, West & Halladay 57 6 ABSTRACT A printing apparatus of the type having an image carrier, a color carrier, a font with a plurality of raised, selectively positionable characters, and a piston assembly whereby activation of the piston assembly causes an image to be transferred from the color carrier to the image carrier. The printing apparatus also includes means for varying the force propelling a portion of the piston assembly toward the font, means for insuring proper alignment of said font and means for advancing the image carrier and the color carrier during the printing cycle.

7 Claims, 15 Drawing Figures u I lli-gllllllilul lfllllllillfillllllllll A U.S. Patent Oct. 14, 1975 Sheet 1 of5 3,912,064

ummmu I. m mmm US. Patent Oct. 14, 1975 Sheet 2 of5 3,912,064

US. Patent O :t.14,1975 Sheet30f5 3,912,064

9 I I I I I I I I I I I I I I I I I I I I I I I I 4 US. I Patent Oct. 14, 1975 Sheet 4 of 5 3,912,064

U.S. Patent ()ct. 14,1975 shws of5 3,912,064

PRINTING APPARATUS WITH FONT ALIGNMENT MEANS BACKGROUND AND SUMMARY OF THE INVENTION Esser Company of Morristown, NJ. Because it was de- I sired that this lettering be uniform and of high quality, the skill of a trained draftsman was, of course, required. As a result these conventional methods were quite expensive, not only because of the skilled draftsman which was necessary, but also because such lettering when done free hand or with the use of lettering aids was quite time consuming. Thus, there was, and still is, a real need for a printing apparatus which can be used to accomplish the high quality lettering desired for engineering drawings and the like and which can be used by a relatively unskilled operator.

Although prior attempts have been made to develop such a printing apparatus, these attempts have not been highly successful. In order to be successful, such apparatus must be capable of lettering directly onto the lettering surface where the lettering is desired, or it must be capable of providing lettering onto an intermediate surface which can quickly and easily be applied to the lettering surface in the location desired. Further, such lettering must be high quality lettering with each character being appropriately spaced from the adjacent character taking into account the difference in printing space required by each character. Still further, such an apparatus must be capable of providing high quality lettering which is of uniform tone and integrity despite the difference in square area of the various characters lettered. Finally, such an apparatus must be operable by a relatively unskilled operator.

In contrast to the prior lettering and printing equipment, the inventors of the present invention have invented a unique printing apparatus with which engineering drawings and the like may be quickly and easily lettered by a relatively unskilled operator in which the characters are properly spaced and of high quality. More specifically, the present invention relates to a printing apparatus of the type having an image carrier and a'color carrier each designed to be guided by appropriate means between a piston assembly and one of a plurality of raised, selectively positionable characters of a font such that when the piston assembly is activated, a piston head is propelled toward the raised character in alignment with the piston head and an image of said raised character is caused to be transferred from the color carrier to the image carrier.

Further, the lettering apparatus of the present invention is provided with means in the form of a character sensing element and a spring adjustment member for varying the force propelling the piston head toward the raised character in'alignment therewith in proportion to the square area of the character being printed. Means is also provided in the form of at least one lock ing pin and a corresponding alignment member for providing proper alignment of the raised character prior to printing and for insuring proper alignment of said character prior to activation of the motor and commencement of the printing cycle. Further, means is provided in the form of a cam assembly and various associated elements, levers and springs for properly spacing adjacent printed characters, taking into account the difference in printing space which the various characters require and for accomplishing proper advancement of the image carrier and the color carrier during each printing cycle to provide proper break away of each from the other and of each from the raised character being lettered, and for varying the printing force in proportion to the square area of the character being lettered. The image carrier designed to be used with the present apparatus is an adhesive backed transparent print media which, after the appropriate combination of characters has been printed thereon, is removed from the apparatus, its adhesive backing removed, and placed on the lettering surface were desired. When this is done, the lettering surface may be blueprinted in conventional fashion with no noticeable difference between the lettering done by free hand or with the use of lettering aids by a skilled draftsman and the lettering done with the apparatus of the present invention.

Accordingly, it is an object of the present invention to provide a printing apparatus capable of being used to perform the lettering on engineering drawings and the like ordinarily performed by a skilled draftsman.

Another object of the present invention is to provide a printing apparatus capable of being operated by a relatively unskilled operator.

Another object of the present invention is to provide a printing apparatus capable of performing high quality, appropriately spaced lettering which could heretofore be accomplished only by a skilled draftsman.

A further object of the present invention is to provide a printing apparatus having means for varying the force with which the piston head is propelled toward the raised character in alignment therewith in proportion to the square area of the character being printed.

Another object of the present invention is to provide a means for providing proper alignment of the character desired to be printed and for preventing the activation of the printing cycle until such proper alignment is achieved.

A further object of the present invention is to provide means for advancing the color carrier during the printing cycle and means for advancing the image carrier during the printing cycle.

A still further object of the present invention is to provide a lettering apparatus including means for variably spacing the printed characters relative to the amount of printing space required for each character.

These and other objects of the present invention will become apparent with reference to the description of the preferred embodiment, the drawings and the appended claims.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the exterior features of the lettering apparatus of the present invention.

FIG. 2 is a top perspective view of the lettering apparatus of the present invention.

FIG. 3 is a perspective, exploded view of the internal elements of the present invention.

FIG. 4 is a plan view showing, among other things, the travel of the image carrier through the apparatus and the means for advancing the image carrier during the printing cycle.

FIG. 5 is a plan view showing the travel of, among other things, the color carrier through the apparatus and the means for advancing the color carrier during the printing cycle.

FIG. 6 is a close-up view, partially in section, of the means for advancing the image carrier.

FIG. 7 is a close-up view of the means for compensating for letter interlocking.

FIG. 8 is a close-up view, partially in section, of a portion of the means for varying the force propelling the piston head upwardly toward the raised character in proportion to the square area of the character being printed.

FIG. 9 is a plan view of one side of the cam assembly.

FIG. 10 is a front view of the cam assembly.

FIG. 11 is a close-up view, partially in section, of the means for activating the printing cycle and insuring proper alignment of the raised character prior to activation.

FIG. 12 is a plan view of the font.

FIG. 13 is a side view, partially in section, of the font.

FIG. 14 is a view, partially in section, of the piston assembly and a portion of the means for varying the force propelling the piston head toward the raised character.

FIG. 15 is a view, partially in section, of the piston assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference first to FIGS. 1 and 2, the printing or lettering apparatus of the present invention includes an external shell 8 covering the frame of the apparatus which is not specifically shown but which is disposed throughout the apparatus for supporting the shell 8 and various shafts, slides, springs and other elements of the apparatus as will hereinafter be described.

Generally, a font 36 (individually illustrated in FIGS. 12 and 13) is positioned on the shell 8, as shown, by means which permit the font 36 to be free spinning or freely rotatable about a center shaft 13 extending upwardly from the surface of the shell 8. As shown in FIGS. 12 and 13, a plurality of raised characters 27 are disposed on the underside of the font 36 near its periphery so that as the font 36 is rotated about the shaft 13, the characters 27 pass a printing station 55 (FIGS. 1 and 2) positioned immediately above a piston assembly. A font retainer 9 adapted for limited slideable movement relative to the shell 8 is positioned such that a portion of the retainer 9 extends over the periphery of the font 36 in the area of the printing station 55 to serve as a means against which the font 36 may be supported during the printing cycle to oppose the upward movement of a portion of the piston assembly against the underside of the font 36 and to oppose movement of the font 36 in response to movement of an alignment means hereinafter described.

An image carrier or print media and a color carrier or ribbon are adapted for movement past the printing station 55 at right angles to each other between the raised character on the underside of the font 36 and the piston assembly so that when the piston is released and caused to move upwardly toward the font 36, an image of the raised character is transferred from the color carrier to the image carrier. It should also be noted that the image carrier passes the center of the font 36 during its advancement and printing is done on a center line of the font 36. As further illustrated in FIGS. 1 and 2, the shell 8 contains a number of external buttons and selector wheels which control the operation of the lettering apparatus. In this respect, a print button 28 operates to activate a motor and commence the printing cycle, a word space button 82 serves to advance the image carrier an appropriate amount between adjacent words, a lettering spacing selector wheel 63 functions to adjust the amount of the image carrier which is advanced between each printed character, a tape advance button 94 operates to advance the image carrier when relatively large advancement is desired and to allow proper cut-off length, a letter interlock button 142 serves to physically backspace the image carrier a specified amount to obtain proper spacings for certain combinations of letters and to compensate for letter interlocking, a font size selector wheel 124 functions to provide for proper ribbon spacing, letter spacing and letter interlock spacing corresponding to the character size of a particular font, and the button 83 operates to cut the image carrier for removal from the apparatus when such is desired.

The internal elements of the lettering apparatus can be seen best with reference to FIG. 3. As shown, the apparatus is driven by a motor 10 having a shaft 12 upon which is mounted an anti-reverse clutch 11 designed, among other things, to permit revolution of the clutch, and thus a cam assembly 14 secured to it, in one direction only. The motor 10 is a conventional skeleton frame motor which, in the preferred embodiment, is a Model No. PF 45 l5Ul2l supplied by Merkle-Korff Gear Co. of Franklin Park, Ill. As illustrated, the clutch 11 is mounted to the shaft 12 and together with a single revolution clutch assembly 15, serves as a rotatable support for the cam assembly 14 during the printing cycle As will be described in more detail throughout the specification and with reference to other Figures, the cam assembly 14 has four cam surfaces which, during a single revolution, drive a piston assembly 49, a means for advancing the print media and a means for advancing the color carrier, and serve to insure proper alignment of the character being printed. The single revolution clutch 15 is a relatively cylindrical element disposed between the clutch 11 and the cam assembly 14 and has means designed to limit the cam assembly 14 and also the motor 10 to single revolution during a printing cycle.

A catch 16 is integrally formed with the clutch 15 and extends outwardly therefrom for engagement with one end of an elongated member 18 of a trigger assembly 19. As illustrated, the member 18 is bifurcated at one end for operative engagement with a trigger stem 20 and a trigger stem connection 21 and is pivotally connected between its ends at the pivot 22 to the frame of the apparatus. The end of the member 18 adapted for engagement with the catch 16 includes a cut-out portion 25 designed to fit over the catch 16 and a latch 24 designed to engage the catch 16 to limit the rotational movement of the clutch l5 and thus the entire cam assembly 14.

The trigger stern connection 21 which is rigidly secured to the trigger stem 20 includes a transversely extending pin 26 adapted to fit between the bifurcated portions of the member 18 for transferring reciprocal movement of the stem to the member 18, thereby causing the member 18 to pivot about its pivot 22. The trigger stem 20 extends upwardly from the connection 21, through one end of a bracket 29 and is connected with' a print button 28 at its upper end. The bracket 29, is pivotally connected to the frame of the apparatus at the pivot and has one end operatively connected with the trigger assembly 19 for transferring reciprocal movement of the stem 20 to a pair of alignment pins or font locking pins 31, 31. The reciprocal movement of thestem 20 is transferred to the bracket 29 by a washer 32 rigidly secured to the stem 20 immediately above the point at which the stem 20 passes through an elongated opening in the bracket 29. When the button 28 is depressed the bracket 29 pivots in a counterclockwise direction about the pivot 30 as a result of engagement with the washer 32. It should be noted that the opening in the bracket 29 must be elongated to compensate for the pivotal movement of the bracket 29 and the reciprocal movement of the stem 20.

The other end of the bracket 29 is rigidly connected with a pin support member 34 which supports a pair of upstanding font locking pins 31, 31. As illustrated best in FIG. 11, the pair of pins 31, 31 are tapered at their upper ends and are adapted to fit into corresponding tapered notches 35 in the underside of the printing font 36 which appropriately positioned to insure proper alignment of the character to be printed, and thus the font 36, during the printing cycle. The pins 31, 31 extend through a pair of conventional spring members 38, 38 which abut a portion of the apparatus frame 39 and which serve to continuously bias the support member 34, and thus the pins 31., 31, downwardly as viewed in FIG. 11. This force on the member 34, and thus the bracket 29, opposes depression of the print button 28 (FIG. 3). A microswitch, illustrated in FIG. 11 by the reference numeral 40, has a switch member 41 connected to the pin support member 34 in such a manner that the upward movement of the support 34 and the pins 31, 31 into the corresponding notches 35 activates the switch which in turn activates the motor 10 (FIG. 3). It should be noted that the switch 40 is positioned such that it will be activated only when the pins 31, 31 are fully extended into the notches 35. This insures proper alignment of the font 36 upon commencement of the printing cycle. For example, if the font 36 is manually positioned so that the pins 31, 31 engage a portion of the font 36 between the notches 35, the switch 40, and thus the motor 10 (FIG. 3) will not be activated when the print button 28 is depressed since the pins 31, 31 will not have moved a distance sufficient to trigger such activation. If the font 36 is positioned so that the pins 31, 31, although not perfectly aligned, have their upper tapered points disposed anywhere in the notches 35, proper alignment will be achieved as a result of the wedging action between the opposing tapered surfaces of the tips of the pins 31, 31 and their respective notches 35 and the upward move ment of the pins 31, 31. For example, if the font 36, as viewed in FIG. 11, were misaligned slightly to the right, upward movement of the pins 31,31 upon depression of the print button 28 would cause the free spinning font 36 to be moved slightly to the left, thereby achieving proper alignment prior to commencement of the printing cycle. It should be noted that the font retainer 9 shown best in FIGS. 1, 2 and 14 has a portion extending over the periphery of the font 36 to oppose upward movement of the font 36 and to allow for the above mentioned wedging action to occur. Thus, it can be seen that the above discussed elements provide a means for properly aligning the character to be printed and insuring such proper alignment upon commencement of a printing cycle.

With general reference to FIG. 3 and specific reference to FIGS. 4, 5, 9 and 10, it can be seen that the cam assembly 14 has four cam surfaces 42, 45, 48 and 50 which function to drive the apparatus of the present invention during a single revolution of the cam 14. First, the cam surface 42, best shown in FIGS. 3 and 4, is located at the outermost periphery of the assembly 14 and functions to drive the image carrier advance mechanism. Second, the cam surface 45, best shown in FIGS. 3, 5 and 10, is disposed on one side of the assembly l4 and drives the color carrier advance mechanism indicated generally in FIG. 5 by reference numeral 46. Third, the cam surface 48, which is an interior surface illustrated best in FIGS. 3, 9, l4 and 15, drives the piston assembly 49. The operation of each of these surfaces and the elements which they drive will be described in more detail later in the specification.

Finally, the cam surface 50, illustrated best in FIGS. 3 and 4, comprises a partially cylindrical surface and serves to lock the trigger assembly 19 out and the font locking pins 31., 31 in during the printing cycle. For example, when the print button 28 is depressed, the trigger stem 20 and connection 21 are moved downwardly causing the member 18 to pivot about its pivot 22 to release the latch 24 from the catch 16. Simultaneously, the downward movement of the stem 20 causes the washer 32 to engage and pivot the bracket 29 about the pivot 30, thereby causing upward movement of the pins 31, 31 into the notches 35 and activation of the switch 40 (FIG. 4) to commence the printing cycle. Activation of the switch 40 in turn causes activation of the motor 10 to rotate theelutch 11 and the cam assembly 14 in a clockwise direction as indicated. As the cam assembly l4 and thus the cam surface 50 rotate, the outer surface 50 engages the portion 51 of the member 18 to keep the trigger assembly 19 and latch 24 open and the pins 31, 31 locked into the notches 35 (FIG. 11). When the cam assembly 14 has rotated sufficiently so that the partial cylindrical surface 50 passes the point 51, the member 18 is caused to move in a clockwise direction as a result of the force exerted on the member 34 by the springs 38, 38 which in turn causes the latch 24 to engage the catch 16 to prevent further movement of the clutch 15 and the cam assembly 14. It should be noted that the clutch 15, in addition to including means to limit the movement of the assembly 14 to a single revolution, also includes an internal spring means for braking the assembly 14 to prevent a sudden stop when th latch 24 engages the catch 16.

With general reference to FIG. 3 and specific reference to FIG. 4, a print media or image carrier in the form of the printing tape 52 is fed from the roll of tape 54, through the means for advancing the media and past the printing station 55. As illustrated, the printing station 55 is located immediately above the piston assembly 49 to enable the printing of a desired character onto the tape 52 through the cooperative action of the piston assembly 49 and the font 36 in the manner hereinafter described. The roll of printing tape 54 is rotatably mounted on the center spindle 56 of a cartridge 58 supported within the frame of the apparatus to allow the tape 52 to be freely taken from the roll 54.

The means for advancing the print media 52 includes a double crank lever or motion transfer arm 59 rotatably supported with respect to the apparatus frame by the shaft 60. One arm of the transfer lever 59 serves to rotatably support a roller 61 adapted for rolling engagement with the cam surface 42. A second arm of the lever 59 is anchored via the spring member 62 to the apparatus frame thereby causing the member 59 to be continuously biased in a clockwise direction and the roller 61 biased toward engagement with the surface 42. The third arm of the transfer lever 59 is connected via the connecting member 64 to one arm of a bellcrank member 65. The connecting member 64 extends through the end of the third arm of the lever 59 and into an elongated slot 66 formed in the bellcrank 65 to transfer movement from the lever 59 to the bellcrank 65. The bellcrank 65 is secured to a spring clutch 69 which in turn is mounted to a shaft 68 in a manner which permits free rotational movement of the clutch 69 and thus the bellcrank 65 about the shaft 68 in a clockwise direction, but which grips the shaft 68 and causes the clutch 69, the bellcrank 65 and the shaft 68 to rotate in unison when the bellcrank 65 is moved in a counterclockwise direction.

As shown best in FIG. 6, a drive roller 70 is mounted to the shaft 68 for rotational movement therewith and an idler roller 71 is disposed immediately above the drive roller 70 in sufficient proximity thereto to cause the image carrier 52 passing between the rollers 70 and 71 to move in the direction indicated upon counterclockwise movement of the drive roller 70. A rubber O ring 72 is disposed in a groove on the periphery of the roller 70 to aid in gripping the print media 52 and advancing it. A letter spacing arm 74 is connected to a second arm of the bellcrank 65 for variably advancing the media 52 during the printing cycle. As illustrated, the spacing arm 74 has a forwardly extending portion 75 adapted for engagement with a notch 76 formed in the letter spacing ring 77 (FIG. 12) of the font 36 to limit the counterclockwise movement of the bellcrank 65 and thus similar movement of the drive roller 70. This in turn limits the advancement of the image carrier 52 during each printing cycle. This arrangement provides means for variably advancing the media 52 in accordance with the particular character being printed. For example, as shown in FIG. 12, the underside of the font 36 includes a letter spacing ring 77 having a plurality of notches 76 of different size for controlling the image carrier advance following the printing of each character. It should be noted that the particular size of the notch 76 and thus the permissible forward movement of the spacing arm 74 during the printing of any particular character will depend upon the character being printed. For example, the size of notch 76 associated with each of the letters I and W will be different since the letter I takes less printing space than the letter W and consequently, the advance of media following the printing of the I would be less. Thus, the notch 76 for the letter I is such that it allows less forward movement of the arm 74 than that for the letter W thus advancing the print media a lesser amount. Thus, the above discussed elements afford a means for properly spacing the characters to be printed despite the amount of printing space required for the various characters.

With reference to FIGS. 3, 4 and 5, the operation of the means for advancing the print media 52 may be described as follows: Following depression of the print button 28, the latch 24 is released from the catch 16 and the cam assembly 14 is rotated in a clockwise direction by the motor 10. Because of the tension in the spring member 62, the roller 61 is caused to roll along the surface 42 during rotation of the cam assembly 14. As the assembly 14 begins to rotate, the shape of the surface 42 is such that it causes movement of the lever 59 in a counterclockwise direction, corresponding clockwise movement of the bellcrank 65 and rearward movement of the letter spacing arm 74. During this movement, the shaft 68 and drive wheel do not rotate because of the orientation of the clutch 69 with respect to the shaft 68. It should be noted that during this portion of the printing cycle, the radial distance between the shaft 12 and the point on the surface 42 engaged by the roller 61 is increasing or remaining constant. If this condition is not met, the media 52 would begin to advance prior to the printing portion of the printing cycle. At a preselected point during the printing cycle, the piston assembly 49 is released and the image of the character being printed is transferred to the media 52. Following this, the surface 42 at the point engaged by the roller 61 is such that the radial distance between the shaft 12 and this point is decreasing, thereby allowing for clockwise movement of the lever 59, counterclockwise movement of the bellcrank 65 and forward movement of the spacing arm 74 into engagement with the notch 76. This movement also causes counterclockwise movement of the shaft 68 and drive wheel 70 and advancement of the print media 52. Although the surface 42 may have several operable alternative shapes, it is necessary that the radial distance between the portion of the surface 42 engaged by the roller 61 and the shaft 12 prior to or during the printing step never be decreasing since this would cause advancement of the print media 52 before or during the printing step, thus resulting in an inferior or improperly spaced printed character.

As further illustrated in FIG. 3, means is provided in the form of the eccentric shaft 53 for adjusting the spacing between adjacent printed characters. As is evident from FIGS. 3 and 4 and from the description of the means for advancing the image carrier the distance which the image carrier 52 is advanced between printed characters is dependent on, among other things, the position of the axle 60 about which the member 59 rotates relative to the surface 42. For example, the greater the distance which the axis 60 is spaced from the surface 42, the smaller the counterclockwise movement during revolution of the assembly 14, and thus, the smaller the advancement of the media 52..Similarly, positioning the axis 60 closer to the surface 42 would result in a greater rotational movement of the member 59 during a printing cycle and thus greater advancement of the media. Because of the eccentric shaft 53, one end of which supports the member 59 and the other end of which is supported by the apparatus frame, the position of the axis 60 about which the member 59 rotates relative to the cam surface 42 can be varied by rotation of the shaft 53. As pointed out above, this in turn varies the advancement of the media between adjacent characters. Rotation of the shaft 53 is accomplished by manual rotation of a letter spacing selector wheel 63 which is operatively connected to the shaft 53 via a plurality of gears 57a and 57b.

Associated with the shaft 68 as shown in FIG. 3 is a means for advancing the image carrier 52 (FIG. 4) to provide proper spacing between printed words. Such means includes a word space lever 78 freely pivotable at one end about the shaft 68 and moveable at its other end between a stop member 79 and one end of a lever arm 80. The arm 80 is pivotally connected at its other end 81 to the frame of the apparatus and is connected between its ends to a word space button 82 operatively disposed in the apparatus frame. Although not specifically illustrated in the drawings, the lever arm 80 has a shoulder portion adapted to engage a portion 84 of a directional clutch 85 to rotate the clutch 85 in a counterclockwise direction upon depression of the word space button 82. The clutch 85 is a conventional directional clutch mounted on the shaft 68 in a manner which causes the clutch 85 to be freely rotated about the shaft 68 in a clockwise direction, but which grips the shaft 68 and rotates it therewith when the clutch 85 is moved in a counterclockwise direction. Thus, depressionof the button 82 and consequential downward movement of the arm 78 and counterclockwise movement of the clutch 85 causes counterclockwise rotation of the shaft 68 and drive wheel 70, thereby advancing the print media. As can be seen, the distance which the media 52 is advanced is directly dependent upon the permissible downward movement of the arm 78 against the vertical stop 79. In this respect, means which will be discussed later is provided for automatically adjusting the vertical position of the stop 79 in relation to the size of the characters being printed, thereby providing the proper word spacing for the various sizes of characters.

Also associated with the shaft 68 and the clutch 85 as illustrated in FIG. 3 is a means for feeding the print media 52 (FIG. 4) when a relatively large advancement of the media is desired such as, for example, when the printing of a particular group of words has been completed and the media is desired to be advanced for cutting and removal from the apparatus. This means includes a cammed gear segment 86 pivotally connected at the pivot 88 to the apparatus frame and having a plurality of gear teeth 89 adapted to operatively engage corresponding gear teeth 90 formed in the clutch 85. Disposed against a lower portion of the gear segment 86 is one end of a spacing linkage 91 which is pivotally mounted to the frame at the pivot 92 and which is connected at its other end to a tape feed button 94. Upon depression of the button 94, the linkage 91 moves about the pivot 92 causing upward movement of the segment 86 and corresponding counterclockwise movement of the clutch 85. As discussed earlier, such movement of the clutch 85 also causes counterclockwise movement of the shaft 68 and drive wheel 70 and advancement of the print media 52. A spring member 97 is attached to the gear segment as shown to bias the segment 86 downwardly and against depression of the button 94. This also biases the clutch 85 in a clockwise direction against the shoulder of the arm 78 (not.

shown) and thus biases the arm 78 upwardly against the end of the arm 80.

Referring again to FIG. 3 and also to FIG. 5, the color carrier or ribbon 96 is fed from a ribbon cartridge 98 of conventional design, past the printing station 55 above and at right angles to the print media 52, through the means for advancing the ribbon and finally onto a take-up spool 99. Although not specifically illustrated, the take-up spool 99 is powered by a conventional stalled synch-motor such as Model No. GL33RA-46 supplied by Hansen Manufacturing Company of Princeton, Ind.

The means for advancing the ribbon 96 during the printing cycle includes a ribbon advance arm assembly 100 pivotally mounted to the apparatus frame at the pivot 101 and having a pair of arms 102 and 104 integrally formed with and extending outwardly therefrom. A roller 105 is rotatably supported by the end of the arm 102 for engagement with the cam surface 45 of the cam assembly 14. As illustrated, the surface 45 is such that rotation of the assembly 14 causes reciprocating movement of the arm 100 about the pivot 101 as a result of engagement between the surface 45 and the roller 105. The end of the arm 104 is operatively connected to a clutch arm 106 by an appropriate connection member 108 for transferring the reciprocating movement of the arm 100 to the arm 106. Also connected with the arm 104 is a spring member 107 biasing the entire advance arm assembly 100 in a counterclockwise direction about the pivot 101. Integrally formed with the clutch arm 106 is a conventional directional clutch 109 similar to the clutch used in the tape advance means (FIGS. 3 and 4). The clutch 109 is mounted to a shaft 110 in a manner such that it is freely movable relative to the shaft 110 when moved in a counterclockwise direction, but such that it grips the shaft 110 and rotates it and the ribbon drive wheel lll therewith when it is moved in a clockwise direction. Similar to the drive wheel 70, the drive wheel 111 includes an 0 ring 112 disposed in a groove about its periphery which, together with the roller 114, causes the ribbon 96 to be moved in the direction shown in response to clockwise movement of the wheel 111. When the printing cycle is commenced, the shape of the surface 45 is such that its engagement with the roller 105 causes clockwise movement of the arm about the pivot 101. During this movement, the clutch 109 and the clutch arm 106 are moved in a counterclockwise direction. Following release of the piston, the shape of the portion of the surface 45 engaging the roller is such that it allows the arm 100 to move in a counterclockwise direction because of the spring 107, thereby causing clockwise rotation of the wheel 111 and advancement of the ribbon 96. Similar to the cam surface 42, the surface 45 may have several operative alternative shapes. However, it is necessary that the surface 45 be such that before and during the release of the piston, the arm is precluded from movement in a counterclockwise direction. If such condition is not met, the ribbon 96 will be advanced during the actual printing step, thereby resulting in an inferior printed character and possible damage to the ribbon 96. It should also be noted that, for optimum performance, the shape of the surfaces 42 and 45 and their relation to their respective operative elements be such that the ribbon is advanced slightly ahead of the print media. Since the ribbon 96 is quite filmsy compared to the image carrier 52 (FIG 4),- movement of the media prior to the ribbon would cause the ribbon to ruffle, thereby resulting in a smudge on the tape. When the ribbon is moved first, however, the tension in the ribbon results in a free break away from the tape. It should be noted that the image carrier or media 52 (FIG. 4) is an adhesive backed printing media of relatively stiff construction which is capable of receiving an image from the color carrier 96 (FIG. when the same are disposed between the raised character of the font and the piston assembly and when the piston head of the piston assembly is propelled toward the raised character as hereinafter described.

Extending outwardly from the upper end of the arm 100 is a pin 116 adapted for engagement with a canted stop member 118 to limit the counterclockwise movement of the arm 100 and thus the advancement of the ribbon 95. The stop member 118 forms the upper portion of a ribbon advance adjustment slide 119 which is slideably connected relative to the apparatus frame and which is biased downwardly by the spring member 121 connected between the frame and the slide 119. As illustrated, the slide 119 contains an elongated opening 120 which, together with the ribbon spacing adjustment bar 122, enables adjustment of the vertical position of the slide 119. This adjustment, in turn, controls the extent to which forward, counterclockwise movement of the ribbon advance arm 100 is permitted. As is evident from the drawings, downward adjustment of the slide 119 permits further counterclockwise movement of the arm 100, while upward adjustment of the slide 119 reduces such permissible movement. The stop member 79 which limits the downward pivotal movement of the word space arm 78 is connected with the upper portion of the slide 119. Thus, adjustment of the vertical position of the slide 119 also adjusts the vertical position of the stop 79 to thereby vary the advancement of the media upon depression of the word space button 82.

As shown best in FIG. 3, the-adjustment bar 122 is an elongated member having one end extending through the opening 120 in the slide 119 and having its other end operatively associated with a font size selector wheel 124. The wheel 124 is mounted on a shaft 125 which is joumaled at each end by appropriate means to the apparatus frame. A gear 126 is likewise mounted to the shaft 125 and contains a plurality of gear teeth adapted for engagement with corresponding gear teeth in a rack 128 integrally formed with the adjustment bar 122. Through this arrangement, rotation of the wheel 124, and thus the shaft 125 and the gear 126, causes lateral movement of the bar 122. It should be noted that the bar 122 is slideably mounted relative to the apparatus frame by appropriate means to permit such movement.

The end of the bar 122 which extends through the opening 120 includes a generally inclined surface having a plurality of steps or intermediate levels 129 intended for engagement with the upper end of the opening 120 to support the slide 119 and oppose the downward force of the spring 121. Because of the inclined nature of the end of the bar 122, the vertical position of the slide 119 will depend upon the lateral position of the bar 122. For example, if the bar 122 is moved toward the left as viewed in FIG. 3 resulting from a clockwise movement of the wheel 124, the slide 119 will be moved upwardly as a result of engagement between the upper end of the opening 120 and the inclined surface at the end of the bar 122. The steps 129 in the inclined surface enable definite vertical positions of the slide to be achieved in response to a particular setting of the wheel 124. As discussed above, such vertical adjustment of the slide 119 controls the extent of ribbon advance and the word space advance of the print media during each printing cycle. The wheel 124 includes various numerical settings corresponding to the various sizes of characters normally printed thereby enabling the operator to properly set the selector wheel to achieve the correct ribbon advance and word space adjustments.

Referring next again to FIG. 3 and also to FIG. 7, a means adapted to compensate for letter interlocking is indicated generally by the reference numeral 130. In the present application, the term letter interlocking refers to the ability of certain combinations of adjacent letters to fit together or interlock because of their particular shape. Because of such interlocking, a space adjustment is required to make such combinations visually satisfactory. For example, if the letters A and V or the letters A and W were printed adjacent to each other without any such adjustment, the space between such letters would appear to be greater than that between other letters because of the particular shape of such letters. To compensate for this, a means 130 is provided for physically moving the image carrier 52 (FIG. 4) backward an appropriate amount to compensate for the apparent difference in spacing.

More specifically, as shown best in FIG. 7, the means 130 includes a first elongated member 131 pivotally connected near its lower end to the apparatus frame at the pivot 132. The upper end of the member 131 is connected to the apparatus frame by the floating pivot 134 which permits limited rotational movement of the member 131 about the pivot 132. A second elongated member or linkage 135 is pivotally connected at one end of the member 131 by the pivot 134 and is connected at its other end to an intermediate portion of the member 131 by a connecting pin 136 in a manner permitting limited pivotal movement of the link 135 relative to the member 131 about the pivot 134. The limitation of such movement is accomplished by an elongated slot indicated by the broken line 138 in the member 131. The upper end of each of the members 131 and 135 have integrally connected thereto, a print media guide 139 and 140 respectively, each of which are designed to guide the advancement of the media 52. Further, when a letter interlocking adjustment is necessary, the guides 139 and 140 are adapted to grip the media 52 and move it to the right as viewed in FIG. 7 to compensate for such letter interlocking.

' Associated with the members 131 and 135 is a means for causing movement of said members in the form of a letter interlock slide 141 which is slideably connected to the apparatus frame by appropriate slide means and which is connected for vertical, reciprocal movement in response to the depression and release of a letter interlock button 142. The movement of the button 142 is transferred to the slide 141 via the connecting link 144 pivotally connected to the apparatus frame at the pivot 145. The slide 141 includes an elongated, diagonally disposed slot 146 through which the pin 136 extends with the slot being disposed such that vertical movement of the slide 141 causes pivotal movement of the member 135 about the pivot 134. Upon upward movement of the slide 141, the link 135 is moved in a counterclockwise direction about the pivot 134 relative to the member 131 as a result of the pin 136 being guided and urged to the right by the lower side of the diagonal slot 146. During this relative rotational movement between the members 131 and 135, the guide 140 is moved upwardly toward the guide 139 until the media 52 is nipped by a portion 148 of the guide 140 and is gripped between the portion 148 and the guide 139. When this is accomplished, the rotated position of the link 135 is such that further upward movement of the slide 141 causes engagement between the pin 136 and the right hand end of the slot 138 to thereby result in clockwise rotation of the member 131 about its pivot 132. During this latter movement of the member 131, the media 52, which has been gripped between the portion 148 and the guide 139, is moved toward the right, thereby affording proper spacing between those certain letter combinations for which adjustment is necessary. It should be noted that the letter interlocking adjustment' is made subsequent to the printing of the first letterof those various combinations of letters and prior to the second. For example, when printing the letters AV, the button 142 is depressed and adjustment is made after the letter A is printed and prior to the printing of the letter V.

can be seen that the extent to which the media 52 is physically moved to the right is dependent upon the extent to which the slide 141 is moved upwardly. This, in turn, is dependent upon the extent to which the button 142 is moved downwardly. As illustrated best in FIG. 3, the permissible downward movement of the button 142 is dependent upon the lateral position of an adjustment slide 149. The slide 149 is slideably connected to the apparatus frame by appropriate means and includes an inclined surface at one end with a plurality of steps or levels 150 adapted for engagement with the link 144 and serving to limit the pivotal movement of the link 144 about its pivot 145. The slide 149 is keyed to the rotation of the font size selector wheel 124 by a rack 151 integrally formed with the slide 145 and a corresponding gear 152 secured to the shaft 125. Upon rotation of the selector wheel 124, the lateral position of the slide 149 and thus the permissible rotational movement of the link 144 and the extent to which the media 52 (FIG. 11) is moved rearwardly is adjusted. Because the ribbon advance and the word space adjustments are also controlled by adjustment of the wheel 124, the various operative elements by which each of the ribbon advance, the word space and the letter interlocking is controlled, are constructed such that for a particular character size setting of the wheel 124, the proper spacing and advancements for such character size will be achieved.

Referring generally again to FIG. 3 and more specifically to FIGS. 4, 5, l4 and 15, a piston assembly 49 is positioned immediately below the printing station 55 and comprises a cylindrical body 154 housing a piston head 155 mounted to one end of a piston stem 158 and a spring member 156 biasing the piston head 155 upwardly. As best illustrated in FIGS. 14 and 15, the piston stem 158 extends through and below the cylindrical member 154 and includes a portion 159 at its lower end to which a roller 160 is rotatably mounted. The roller 160 is designed for rolling engagement with the internal cam surface 48 shown best in FIGS. 14 and 9.

One end of the spring 156 is disposed against the bottom surface of the piston head 155 and the other end is supported by a spring retaining member or cup 162 positioned immediately below the spring 156. The cup 162 is supported at its lower end by a spring lifter 165. During the printing cycle, the stem 158 and piston head 155 are caused to move downwardly in opposition to the force of the spring 156 as a result of engagement between the roller 160 and the cam surface 48. When the rotation of the cam assembly 14 is such that the roller 160 reaches the point 164 of the surface 48 (FIG. 9), the roller 160 is released and the spring 156 which has been compressed during downward movement of the head expands, propelling the piston head 155 upwardly toward the raised characters on the underside of the font 36 thereby transferring the image of the raised character from the color carrier 96 to the image carrier 52 disposed immediately below the raised character. When. this is accomplished, the printing step is complete and the piston assembly elements return to the piston illustrated in FIG. 14. As shown in FIGS. 14 and 15, the color carrier 96 and the image carrier 52 cross at right angles to each other immediately below the raised character 27 which is aligned with the printing head 155'. It should be noted that the image carrier 52 is disposed below the color carrier 96. Although the printing head l5,5 may be composed of a variety of materials, it is important that such material have a good memory so that impressions of previously printed characters do not remain in the head and that the material be softer than the material from which the raised characters on the font are composed to reduce wear on the font. It should also be noted that a font retainer 9 is slideably mounted to the frame of the apparatus with a portion extending over the periphery of the font 36 to oppose and prevent upward movement of the font 36 as a result of the piston head 155 being propelled toward the font and as a result of the alignment pins 31, 31 (FIG. 11) being moved upwardly into the notches 35.

Associated with the piston assembly 49 is a means for varying the vertical position of the retaining cup 162 and thus the base against which the spring member 156 rests. As will be discussed below, this also varies the upward force of the spring 156 on the piston head 155 when the piston roller has been released from the surface 48 and thus the force with which the head 155 is propelled toward the raised characters 27 of the font 36. In general, such a means is designed to vary the force urging the head 155 toward the font 36 in proportion to the size or area of the character being printed. Thus a period or a comma" would be printed with less force than, for example, the letters M or Such means is necessary to achieve uniform printing of the various characters.

The means for varying the printing pressure exerted by the piston head 155 on the raised characters 27 of the font 36 includes a spring lifter'l65 having one end integrally connected to a rack 166, and having its other end extending through an elongated opening 168 in the cylinder member 154 and engaging a lower portion of the retaining cup 162. With this arrangement, the vertical position of the cup 162 is dependent upon the vertical movement of the lifter 165. Associated with the rack 166 and having teeth adapted for engagement with corresponding teeth on the rack 166 is a gear 169 whose rotational movement causes vertical movement of the rack 166 and the lifter 165. With reference to FIG. 3, the gear 169 is mounted to one end of a shaft 170 whose other end is connected to a gear 171. The shaft 170 is supported by appropriate means to the apparatus frame. The gear 1.71 is operatively connected via an intermediate gear 172 to a rack 174 mounted for sliding movement by appropriate slides to the apparatus frame. A character sensing means in the form of the sensing pin 175 is connected to the top of the rack 174 as shown best in FIG. 8 and extends above the surface of the apparatus 176 for engagement with a portion 178 on the underside of the font 36 adapted for engagement with the pin 175 for limiting the lateral movement thereof. This controlled lateral movement of the pin 175, as a result of the corresponding operation of the racks 174 and 166 and the gears 172, 171 and 169, controls the vertical position of the cup 162 and thus the force with which the head 155 is propelled upwardly toward the font 36 during the printing cycle. For example, referring to FIGS. 14 and 15, if the vertical position of the cup 162 is near the bottom of the cylindrical member 154, the force by the spring 156 propelling the piston head 155 upwardly when the roller 160 is released from the surface 48 is much less than if the vertical position of the lifter 162 is higher since the spring 156 would not be compressed as much. It should be noted that the portion 178 (FIG. 8) corresponds to the pressure control ring 177 (FIG. 12) disposed on the underside of the font 36 whose particular shape and orientation relative to the characters on the font is such that the movement of the pin 175 against the portion 178 as shown in FIG. 8 provides for the proper vertical positioning of the cup 162, and thus the proper printing pressure relative to the size or area of the character being printed. It should be noted that this means varies the printing force so that it is generally in proportion to the size of the character printing. Ideally, the force would vary in direct proportion to the square area of the character printed.

With general reference now to FIG. 3 and more specific reference to the other figures, the general operation of the lettering apparatus of the present invention may be understood as follows: First, as illustrated in FIGS. 1 and 2, the font 36 is manually rotated about its center support shaft 13 until the character desired to be printed is positioned in alignment with the printing station 55. Although exact alignment of the character with the printing station through this manual rotation is not necessary, it is necessary that the character be sufficiently aligned so that the font locking pins 31, 31 will engage the tapered notches 35 as shown in FIG. 11. After the desired character is so aligned, the print button 28 is depressed causing the member 18 to pivot about the point 22 releasing the catch 16 and causing the font locking pins 31, 31 to be moved upwardly toward engagement with the tapered notches 35 (FIG. 11) on the underside of the font 36. When the pins 31, 31 are fully extended into the notches 35, the motor 10 is activated, causing the cam assembly 14 to rotate about the shaft 12. Such activation of the motor 10 constitutes the commencement of the printing cycle. During the initial portion of the printing cycle, the surface 42 engages the roller 61 in a manner which causes counterclockwise movement of the member 59 about its axis 60. This movement, in turn, causes clockwise movement of the bellcrank member 65 about the shaft 68. During this same initial portion of the printing cycle, the surface 45 engages the roller 105 to pivot the assembly 100 in a clockwise direction above the pivot 101. As illustrated, this movement causes corresponding counterclockwise movement of the arm 106 and 6 the clutch 109. Also, during this initial portion of the printing cycle, the surface 48, best illustrated in FIGS. 9 and 14, engages the roller 160 attached to the end of the piston stem 158. As the cam assembly 14 and thus the surface 48 rotate, the engagement between the surface 48 and the roller 160 causes downward movement of the printing head 155 and compression of the spring 156.

When the cam assembly 14 has rotated to the point at which the roller 160 reaches the point 164 of the surface 48 (FIG. 9), the piston assembly is released, causing the piston head 155, as a result of the spring 156, to be propelled upwardly toward the raised character on the underside of the font 36. Because the image carrier and the color carrier are disposed immediately below the raised character, an image of the raised character is transferred from the color carrier to the image carrier. The propelling of the piston head 155 toward the font 36 is referred to as the printing step. Following the printing step, the elements of the piston assembly 49 return to the position illustrated in FIG. 14. Also, following the printing step, the surfaces 42 and 45 of the cam assembly 14 are such that clockwise movement of the member 59 and counterclockwise movement of the assembly are permitted. These movements, in turn, permit counterclockwise movement of the tape drive wheel 70 and clockwise movement of the ribbon drive wheel 111 respectively. As described above, the movement of the wheels 70 and 111 cause appropriate advancement of the image carrier and the color carrier so that the image carrier and color carrier are appropriately positioned for the next printing cycle.

As also described in the above specification, the preferred embodiment of the printing apparatus of the present invention includes a means for variably spacing the characters being printed in accordance with the space needed to print such characters, a means for backspacing the image carrier a specified amount to compensate for the interlocking of certain letter combinations, and a means for varying the force with which the piston head is propelled against the raised character on the underside of the font in direct proportion to the square area of the character being printed. Finally, means are also provided for advancing the image carrier to provide proper spacing between words and a means for adjusting the above features and elements to provide for proper spacings, advancements and backspacing in accordance with the particular size of characters being printed.

Although the description of preferred embodiment of the present invention has been quite specific, it is contemplated that various modifications may be made to the embodiment disclosed without deviating from the spirit of the present invention. Consequently, the scope of the present invention is intended to be dictated by the appended claims, rather than by the description of the preferred embodiment.

We claim:

1. A printing apparatus of the type having an image carrier and a color carrier, said printing apparatus comprising:

a printing station;

a font having a plurality of raised characters with a plurality of different surface areas, each of said characters selectively positionable in alignment with said printing station to thereby define an aligned character;

means for exerting a printing pressure against said aligned character and said printing station including an adjustable spring support means and a spring means for propelling a piston head toward said aligned character wherein the force propelling said piston head is dependent upon the position of said support means and means for advancing said image carrier relative to said printing station subsequent to each transfer of an image of said aligned character to said image carrier; sensing means cooperating with said font for sensing which of said raised characters is aligned with said printing station; means cooperating with said sensing means for varying said printing pressure in proportion to the surface area of said aligned character including adjustment means for adjusting the position of said spring support means;

said printing apparatus being further defined in that said font includes a pressure control ring and said sensing means includes a sensing pin cooperating with said adjustment means and adapted for limited movement into engagement with said pressure control ring, the shape and orientation of said pressure control ring beging such that engagement therewith by said sensing pin properly adjusts the position of said spring support means.

2. A printing apparatus of the type having an image carrier and a color carrier, said printing apparatus comprising:

a printing station;

a free spinning, manually rotatable font mounted on a shaft for unrestricted manual rotation having a plurality of raised characters, each being selectively positionable in approximate printing alignment with said printing station to thereby define an aligned character;

means for causing an image of said aligned character to be transferred to said image carrier during a printing cycle;

means for guiding said image carrier between said aligned character and said printing station and for advancing said image carrier relative to said printing station subsequent to each transfer of an image of said aligned character to said image carrier; alignment means for further aligning said aligned character into printing alignment with said printing station including a first tapered alignment member associated with said printing station and a second tapered alignment member associated with and moveable with said font and adapted for engagement with said first alignment member for such further alignment, said first and second alignment members being engaged with each other only during a printing cycle, thus giving said font its free spinning characteristic, said alignment means having a font retaining portion extending over said font in alignment with said printing station to oppose movement of said font as a result of engagement between said first and second alignment members.

3. The printing apparatus of claim 2 wherein said first alignment means includes at least one alignment pin having a tapered end and said second alignment means includes a tapered notch adapted to receive the tapered end of said alignment pin.

4. The printing apparatus of claim 3 wherein said alignment pin is adapted for movement toward said tapered notch.

5. The printing apparatus of claim 4 having a switch means for commencing the printing cycle upon activation of said switch means, said switch means being connected with said alignment pin such that said switch means is activated only when proper alignment of said aligned character is achieved.

6. The printing apparatus of claim 5 wherein said alignment means includes a pair of spaced alignment pins, each having a tapered end adapted for engagement with a pair of corresponding spaced notches in said font.

7. The printing apparatus of claim 2 wherein one of said first and second alignment members is moveable toward the other for engagement therewith in a direction substantially parallel to the longitudinal axis of the shaft upon which said font is mounted for rotation. 

1. A printing apparatus of the type having an image carrier and a color carrier, said printing apparatus comprising: a printing station; a font having a plurality of raised characters with a plurality of different surface areas, each of said characters selectively positionable in alignment with said printing station to thereby define an aligned character; means for exerting a printing pressure against said aligned character and said printing station including an adjustable spring support means and a spring means for propelling a piston head toward said aligned character wherein the force propelling said piston head is dependent upon the position of said support means and means for advancing said image carrier relative to said printing station subsequent to each transfer of an image of said aligned character to said image carrier; sensing means cooperating with said font for sensing which of said raised characters is aligned with said printing station; means cooperating with said sensing means for varying said printing pressure in proportion to the surface area of said aligned character including adjustment means for adjusting the position of said spring support means; said printing apparatus being further defined in that said font includes a pressure control ring and said sensing means includes a sensing pin cooperating with said adjustment means and adapted for limited movement into engagement with said pressure control ring, the shape and orientation of said pressure control ring beging such that engagement therewith by said sensing pin properly adjusts the position of said spring support means.
 2. A printing apparatus of the type having an image carrier and a color carrier, said printing apparatus comprising: a printing station; a free spinning, manually rotatable font mounted on a shaft for unrestricted manual rotation having a plurality of raised characters, each being selectively positionable in approximate printing alignment with said printing station to thereby define an aligned character; means for causing an image of said aligned character to be transferred to said image carrier during a printing cycle; means for guiding said image carrier between said aligned character and said printing station and for advancing said image carrier relative to said printing station subsequent to each transfer of an image of said aligned character to said image carrier; alignment means for further aligning said aligned character into printing alignment with said printing station including a first tapered alignment member associated with said printing station and a second tapered alignment member associated with and moveable with said font and adapted for engagement with said first alignment member for such further alignment, said first and second alignment members being engaged with each other only during a printing cycle, thus giving said font its free spinning characteristic, said alignment means having a font retaining portion extending over said font in alignment with said printing station to oppose movement of said font as a result of engagement between said first and second alignment mEmbers.
 3. The printing apparatus of claim 2 wherein said first alignment means includes at least one alignment pin having a tapered end and said second alignment means includes a tapered notch adapted to receive the tapered end of said alignment pin.
 4. The printing apparatus of claim 3 wherein said alignment pin is adapted for movement toward said tapered notch.
 5. The printing apparatus of claim 4 having a switch means for commencing the printing cycle upon activation of said switch means, said switch means being connected with said alignment pin such that said switch means is activated only when proper alignment of said aligned character is achieved.
 6. The printing apparatus of claim 5 wherein said alignment means includes a pair of spaced alignment pins, each having a tapered end adapted for engagement with a pair of corresponding spaced notches in said font.
 7. The printing apparatus of claim 2 wherein one of said first and second alignment members is moveable toward the other for engagement therewith in a direction substantially parallel to the longitudinal axis of the shaft upon which said font is mounted for rotation. 